US1993632A - Machine for turning lasts and the like irregular forms - Google Patents

Description

March 5, 1935.

Filed Sept. 12. 1951 MACHINE FOR TURNING LASTS AND THE LIKE IRREGULAR FORMS 4 Sheets-Sheet 1 134 52 39 :13 43 E L o 34 35 o 16 o o L I E 41 25 27 f 25 ,L 33 105 21 e L. 2 42 0 o o o O o 14 17 m 12 12s 66 2 e2 100 so 1- o o I i 4 I: I" 9 141 127 -14z 150 A A 2 72 1 ,fzzvczzi' i a ay" March 5, 1935 MACHINE FOR TURNING LASTS AND THE LIKE IRREGULAR FORMS 'H. W. SPRAGUE Filed Sept. 12. 1931 4 Sheets-Sheet 2 March 5, 1935. H. w. SPRAGUE 1,993,632

N? LASTS AND THE LIKE IRREGUIJAR FORMS MACHINE FOR TURNI 4 Sheets-Sheet 5 Filed Sept. 12. 1951 March 5, 1935. H. w. sPRAeuE TURNIkiG LASTS AND THE LIKE IRREGULAR FORMS Patented Mar. 5, 1935 UNITED STATES PATENT' O E:

MACHINE FOR TURNING LASTS AND THE LIKE IRREGULAR FORMS Harold W. 'Sprague, Brockton, Mass. -Application September 12, 19 31, Serial No. 562,529

' 2 Claims. (01. 142-15) My present invention is a novel and improved machine adapted primarily. for automatically cutting and forming irregularly shaped articles such as a shoe last, wherein the contour of a finished model is utilized and which. model the cutting instrumentalities reproduce from a larger block.

An important object of my present invention is the provision of means which will enable the cutting devices to follow much smaller and more intricate curves, particularly concave curves on the model and to reproduce such contours in the work being cut. I

Heretofore in turning apparatus of similar kind it has been universally customary to utilize'a Wheel to follow the contour of the model. This wheel actuates a swinging frame carrying the model and block to be out, and originally in last turning lathes such model wheels were from twelve inches to thirteen inches in diameter. Such a model wheel, however, could not follow an internal or concave curvature of smallerdiameter than that of the Wheel itself, but would bridge across any contour of the model ona concave curvature of lesserdiameter than that of the wheel. With theco-nstantly changing designs on shoe lasts and more involved contours, such model wheels were reduced in diameter until seven or eight-inches whichseemed to be the smallest. diameter commercially and practically possible and feasible, particularly where the axis of, rotation of the cutter head utilized was parallel with the axis of rotation of the work. In order to overcome the difiiculty above noted in the effort to follow more sharply shaped lasts, the next development was. toincline the axis of rotation of the cutter. head and to vary the shape, form and contour of the cutter itself. By this means, viz., inclining the cutter head axis to as sharp an angle as forty-five degrees, itwas possible to operate such lathes commercially and greatly reduce the diameter of the model wheel. In my present invention I have devised a novel cutter head shown, described and claimed more in detail in my copending application Ser. No. 555,445 now Patent No. 1,935,337, issued Nov. 14, 1933 and have devised a. novel form of follower to contact with the model, whereby I am enabled to make a last with the cutter head mounted at right angles-the most eflicient and desirable position with regard to the workand capable of following internal contours and curvatures on a model with as small a radius as threequarters of an inch or even less if desired.

An important advantage in the feature just described is that I may, by my novel machine and apparatus, enable the cutter to more closely, accurately and completely followthe model than has heretofore been possible; enable-thecutter to even form such slightint'ernal recesses as now required in lasts for use inmaking the metatarsal arch support of the shoe to be built on such lasts; thus substantially, and in many instances almost entirely eliminating the hand work heretofore required in finishing lasts.

A further important and novel feature of my present invention consists in the arrangement and construction of my novel last lathe which permits an electric motor to be utilized'to turn the cutter and yet which will entirely free the cutter from vibration of the motor and conversely free the motor from any chattering which might beoccasioned by the cutter head encountering diliicult portions of the work being operated on. Thus the 'motor will run more smoothly and the cutter head will also run more smoothly than heretoforepossible, increasing the efiiciency and smoothness of the cutting action, eliminating noise and wear, and also permitting substantially increased speed of rotation of the cutter. r

This feature is most important in my present invention and the advantages incident thereto will be readily appreciated by those skilled in this art. 1 In carrying out this feature of my invention I arrange the motor and the cutter on separate carriages together with means acting automaticallyto move both the motor carriage and the cutter carriage simultaneously during the progress of the cutting action, as the same are fed lengthwise of the work while each is free of the transmission 'of the vibration of either to the other as above noted. Heretofore it has been customary to mount the motorand the cutter on the same carriage and consequently both the weight of the motor and the motor vibration were transmitted to the cutter, resulting in unsatisfactory work, chattering andconseguently uneven operation of the, cutter and necessarily limiting the speed of rotation of both motor and cutter.

A .still further and important feature of my present machine and invention is the novel ar rangement, construction and universal adjustability of thefollower on the model. 'As above noted, it has been heretofore universally customary toutilize a wheel which would roll on the model as it is turned and which would progress with the feeding action of the cutter on the block being shaped.

Further features, novel combinations and advantages will be hereinafter more fully pointed out and claimed.

Referring to the drawings, illustrating a preferred embodiment of my present invention,

Fig. 1 is a general view of my improved turning lathe;

Fig. 2 is a plan view of a portion of the frame carrying the cutter head;

Fig. 3 is a fragmentary vertical cross sectional view illustrating the cutter head and motor on separate carriages; 1

Fig. 4 is a fragmentary View substantially at right angles of the showing of Fig. 3;

Fig. 5 is a fragmentary view of the model ball and carrying devices;

Fig. 6 is a View of a modified form of adjustments for the model ball;

Fig. '7 is an enlarged cross sectional view of the model ball; I

Fig. 8 is an enlarged cross sectional view of the cutter head, shaftand bearings;

Figs. 9 and 10 are enlarged fragmentary views illustrating my novel cutter head as more fully described and claimed in said copending application Ser. No. 555,445; and

Figs. 11, 12, 13, 14, and 16 are diagrammatic views illustrating the impossibilities of a model wheel reproducing an. internal curve of less diameter than that of the wheel while graphically showing the facility of my inventionv in reproducing such internal curved contours of extremely small diameter.

Referring to the drawings, I utilize a well known and standard type of last lathe construction comprising a set of vertical standards 1, 1, cross frames 2 and 3 provided with braces 4 from the upper end of the standards to the cross frame 3. Mounted at the upper end of the standards 1, 1, on pivots or studs 6, 6, is swung a swinging frame 12, 12, carrying cross rods 13 and 14. The fixed frame work is arranged to carry the cutter and the model contacting member. In my present invention this member is a spherical ball and the cutter 25 is preferably as shown in my said copending application, Ser. No. 555,445, as already noted.

The swinging frame 12, 12 is arranged to carry the model 31, with which the member 30 is in contact and the block 26 on which the cutter 25 is operated. In order to rotate the model 31 and the block 26 they are mounted on centers in the swinging frame and are arranged for rotation at the same speed. As shown in Fig. 1, cross bars 13 and 14 on the swinging frame are supported by braces 15, 15, which are pivotally se-.

cured to bracket members 16 and 17 respectively, these brackets extending from 13 to 14 and being fixed in their respective positions.

Mounted between the brackets 16 and 17 on suitable journal bearings is a shaft 20 carrying a live center 21 to engage one end of the block 26, the opposite end being engaged on an idle center 27 carried by a bracket 28 adjustably secured on the cross bars 13 and 14. This bracket has the usual adjustments sliding on the cross bars 13 and 14 to enable the same to hold and secure in position a block 26 of any desired length.

The model 31 also mounted in the swinging frame is held by a live center 33 passing through a suitable bearing on a bracket 34 fixed to the cross bars 13 and 14 and with a sliding bracket 35 adjustably securedto the crossbars 13and 14 having a center 36 holding the opposite end of the model last 31.

In order to rotate the block 26 and model 31 at the same speed, gear wheels, of similar diameter, 37 and 38 are mounted respectively on shafts of the live centers 21 and 33 and are turned by pinions 39 and 40 on a shaft 41 mounted in suitable bearings on the fixed brackets 1'7 and 34, as clearly shown in Fig. 1, said shaft 41 carrying a pulley 42 which is rotated by a belt 43 from a pulley 44 secured in a bearing 45 mounted at the top of the machine and parallel to and near the axis of the swinging frame 12.

The pulley 44 has secured at the other end a corresponding pulley 46 rotated by a belt 47 on a pulley 48 secured to a shaft 50 supported in rigid bearings at the upper part of the frame 1, 1 and carrying on its outer end portion a pulley 51 rotated by a belt 52 connected to a driving pulley 53 on a shaft 54 driven by any suitable source of power.

The construction thus far described may be of any usual or standard type'of lathe and the cutter head, model contact sphere and my novel driving mechanism therefor will now be described.

Mounted on the cross frames 2 are the beveled guide and flat guide '61, the guide 60 being preferably beveled to fit within the groove of the guide 62 mounted thereon.

Slidably resting on the guide 62 and guide 61 is a frame work carrying the cutter head comprising a base 66 substantially rectangular in form and of sufficient width to give a firm bearing on the guide 62 and guide 61; said base having standards 67 and 68 carrying bearings at the upper portion for the cutter shaft '70 on which my novel form of cutter head 25 is secured. As previously explained, I am enabled by my present invention to utilize a cutter head and shaft positioned substantially at right angles to the work or block 26. on which the cutter head 25 operates and at right angles also to the line of feed of the cutter frame 66 as it is moved progressive- 1y on the guide 62 and guide 61, lengthwise of the block 26 during the cutting operation.

Furthermore, an important feature of my present arrangement, wherein the cutter head and shaft are thus positioned directly at right angles, is that I am enabled to form the bearings for the cutter head and shaft closer to the work and thus fit or secure the cutter head 25 very closely to the bearings of the cutter shaft 70. This eliminates vibration, distortion, or springing of the cutter shaft,-a serious difficulty in prior constructions where the cutter head and shaft were positioned at an acute angle and hence with the shaft extending a relatively long distance in front of the bearings in order to provide a clearance of the first bearing or that nearest the block and work. A long cutter shaft with the cutter at the end substantially removed from thefirst bearing, as in old construction, causedconstant chattering, vibration, and other difficulties often necessitating a slow speed.

By my improved and novel arrangement, however, with the cutter head itself and all strains involved in the cutting action on hardwood, such as rock maple, these prior difficulties are eliminated and I am enabled to rotate the cutter head at greatly increased speed if desired, thus insuring smoother action, more uniform operation, and freedom from vibration.

The cutter head 251is, as 'ex 'lain'ed in my said bearings on-the vertical supports 67 and 68 on the shaft 70 to. receive a belt '72 connected with a pulley 73 rotated by an electric motor 75.

An important feature of my present improved machine is that the motor -75 is mountedseparately from the cutter shaft 70 thus eliminating from the cutter shaft any vibration of the motor and similarly eliminating from the motor anyvibration caused from the cutter head. This is a most important advantage in devices of the kind herein described, as I provide rigid supports for the cutter shaft directly on the fixed frame of the machine and separate and distinct rigid supports for the motor, also secured to the fixed frame work and then I provide means which will feed both the motor and the cutter head during its progressive action, at the speed desired, lengthwise of the block 26 being out. While separate feeding devices may be utilized both for the motor support and for the cutter head, providing they are moved at substantially uniform speed, yet I have devised a novel vibration-free connection between the cutter head and motor operable from one source of power.

The cutter head supporting frame has already been described and the motor support will now be described.

As shown in Figs. 2, 3, l and 5, I secure a pair of guide rods 76 and 77 lengthwise of the line of feed desired for the cutter and motor. The rod '77 is preferably mounted in suitable sockets v'78 in the frame 1, 1 (see Fig. 2), and the rod '76 may be similarly mounted, but as. herein shown, I have secured one end to a socket 79 in the frame 1, 1, and the other end is mounted on a bracket 80 bolted at 81 to the member 2 and at its opposite end having a recess through which the shaft 77 is passed and carrying the socket 82 for the end of the rod 76. This gives ample length for the travel of the support carrying the motor 75.

Mounted on the rods 76 and 77 by blocks 83 and 84 (see Figs. 3 and 4), is a cross brace 85 carrying a depending bracket 86 to which the motor support 87 is secured. Preferably I arrange this support 87 to constitute a belt-tightener between the motor 75 and the pulley on the cutter head shaft 70. For this purpose the lower end of the bracket 86 is recessed to receive a pivot pin 90 passing through corresponding recesses in a pair of projecting ears or lugs 91 on the motor support 87. Adjusting means to oscillate and lock in position the motor support 87 on the pivot 90 is provided by a pair of adjusting screws 92 and 93 (see Fig. 4). The adjusting screw 92 is arranged through a tapped recess through the bracket '86 in convenient position to bear against a portion of the motor support 87 and constitute a thrust bearing." The adjusting screw 93 is threaded through a correspondingly tapped lug 94 also on the bracket 86 and passesfreely through an opening in the adjacent portion of the motor support 87 to constitute a tightening screw.

By manipulating the thrusting screw 92 and tightening screw 93 the motor and support will be oscillated on the pivot 90 and thus operate as a belt-tightener, as above explained.

With the motor carrying support thus mounted work.

independently onthe rods 76 and '77, andslidable freely thereon and with the cutter shaft frame mounted on the slides 62 and 61, it will thus be seen that each is independently supported on the frame work and transmission of vibrations from one to the other is eliminated. This is an important feature, as above explained, and results in a greatly increased smoothness of operation of the lathe, permitting added speed.

In order to move the cutter carrying slide and motor carrying slide in unison I impart feeding motion to'the cutter slide 66, as willbe explained, and move the motor slide therewith by securing to the under part of the cutter slide 66 a depending member 96 fixed to the cutter slide 66 in N convenient position to engage the blocks 83 and 84 supporting the motor. Preferably I arrange the blocks 83 and 84 slightly spaced on the rod '77. Thus with the depending member 96 therebetween movement lengthwise of the rods 76 and 77 will be imparted to the motor simultaously with the corresponding movement of the cutter carriage 66.

I may find it desirable to mount the cutter shaft '70 in ball bearings, although this is optional; but in view of the smooth operation of my separately slidable motor and cutter supports, it is feasible in this construction, and as shown in Fig. 8, ball bearing mounting and raceways of any desired form are illustrated at 193. I also provide the usual hand wheel 194 on the cutter shaft 70, which may be integral with the pulley 71 The slide carrying the model contact member which at the present instance is -my novel spherical ball 30 is of usual form, comprising the carriage 100 mounted to slide on the guides 62 and 61, as explained in connection with the cutter carrying frame,- and as clearly shown in Fig. 5. The carriage 100 has supports 101 and 102 for the plate 103. Said plate has a pair of dovetailed grooves in which the model carrying slide ,105 is adapted to move and may be locked in position where desired by rotation of the locking nut 106 tapped through a threaded recess in a convenient portion, as shown'in Figs. 4 and 5. The slide is moved inwardly or outwardly for adjustment of the contact member 30 on the the slide 105, as shown in Figs. 5 and 7, or I may secure same in apivotal position, as shown in Fig. 6.

Referring toFigs. 5 and '7, the slide 105 is preferably recessed as indicated at 116, to receive the support 107 on which the contact ball 30 is mounted. A pair of screws 108 tapped into the support 107 through corresponding countersunk recesses in the slide 105, as clearly shown in Fig. 7, secures the same to the slide. In order to mount the contact sphere or ball 30, which is to roll upon the model and effect a swinging of the frame, I provide at the end of the support 107 a stud 110 preferably shouldered, as shown at 111. to constitute a support and pivot for the ball30. I also bevel the outer portion of the support 107 as shown at 112, which aids in giving clearance to this member and to permit the ball 30 to follow inturned or ccncaved curves of extremely small radius.

In order to mount the ball 30 so that it will be firmly held and yet turned freely on the shoulder stud 110, I bore through the stud 110, as shown.

I may secure the member 30 rigidly to the head of the retaining screw 115.

Referring to the modified form shown in Fig. 6, I provide a vertical adjustment as well as that afforded by movement of the slide 105. In this arrangement I mount the support 107 'on a pivot 1'20 and secure same in a V-shaped recess 121 in the slide 105. I also provide a pair of tapped recesses diametrically opposed and containing threaded contact members 122 and 123 so positioned as to bear upon the support 107 and 0scillate it about the pivot and hold the same imposition to which it may be adjusted, by rotating said contact members 122 and 123, as will be readily understood.

The means of rotating the model 31 and block 26 in the swinging frame has already been described and in order to feed the cutter carriage 66 and contact carriage 100 longitudinally of the work on their respective slides, I secure same together by a pair of telescoping bars 125 and 126 adapted to be united in adjusted position by passing through a block 127 and clamped by a screw 128. Thus they will be fed 'in unison, this being the usual construction.

In order to effect the feeding movement of the carriages 66 and 100, I provide pulleys 130, on the shaft 50, and 131, on the shaft 133, arranged for variable speeds, said shaft 133 being mounted in the frame 1, 1 and carrying at its outer end a pulley 134 to which the belt 135 is led to a pulley 136 on a shaft 137 at the base of the frame.

This shaft 137 has a worm 138 arranged to mesh with the gear 139 on a shaft carrying a gear 146 and through pinions 141 and 142 operating on a rack secured underneath the carriage 66 and thus imparting desired feed to the cutter head 25 and model contact ball 30.

An important feature of my present invention, as briefly explained and above outlned, is the arrangement of the novel ball 30 cooperating with the novel cutter head 25, permitting the lathe to operate much more efiiciently than has heretofore been possible and to follow involved contours on the model of extremely small radius.

Referring to Fig. 11 is illustrated in diagrammatic form a cross sectional portion of a typical shoe last which is rotated in the lathe and around which the model wheel rolls. As above explained, it has heretofore been found impractical to have a model wheel rolling on an irregular form such as a last 160 of less than seven inches in diameter, such a wheel being shown in dotted lines at 161. Consequently, as the last 160 and wheel 161 rotate, swinging the frame carrying the block 26 to be cut, the cutter, irrespective of its size, position or shape will follow on the block 26 the movement effected by the wheel 161. In other words, the lathe could not cut a sharper angle or a concave contour which was on a radius less than that of the model wheel 161. By my improvement with the ball 30 of extremely small diameter and cooperating with the mushroom formed cutter 25, it will be seen on reference to Fig. 12 that a last 160 having a curved contour at 162 will be readily followed by the ball 30 and the same contour reproduced in the block 26 by my cutter 25.

It is customary at present to make lasts with such small and sharply curved recesses in the tarsal arch supporting feature.

ably, also, the ball 30 is countersunk to receive 'ball of the last to provide a corresponding meta tarsal arch supporting projection or structure in the shoe to be made thereon. He'ret'ofore it has been impossible in any last turning lathe to provide either afollower or a cutter which would turn out a last including the recess for the meta- Consequently "all such prior devices have had to be made by laborious and highly skilled hand labor.

Furthermore, it was impossible to accurately position and form such recesses by hand gouging. By my present invention, as clearly illustrated in Figs. 13 and 14, my contact ball 30 and cutter 25 will readily follow and reproduce as sharply a concave metatarsal recess as is ordinarily desired in a last, as shown at 165 m the last 16 1, Figs. 13 and 14. This feature is a distinct improvement in the art of last turning or in turning any irregular articles with concave contours of less radius than that of the former seven inch model wheel which rolls in contact with the model to be reproduced. a

A further important feature is-that I provide.

the contact ball 30 and the smallest cutting diameter of the cutter 25 on substantially the same radius. Thus the contact ball and the cutter automatically follow and accurately reproduce curves of an extremely small radius, which were heretofore deemed impossible on turning machines, as well as following and reproducing all other portions heretofore made on turning lathes of this kind. In fact, I can make the contact ball and cutter of sufficiently small radius to cut on concave contours of a fraction of an inch.

Furthermore, the fact that my improved lathe and apparatus, when used for turning lasts, is of greatly increased accuracy than heretofore possible, also eliminates to a large degree the subsequent operation of shaving the last to remove ridges left by the feeding of the turning cutter. This is a great saving and a most important and novel feature.

My invention is further described and defined in the form of claims as follows:

1. In a turning lathe of the kind described for reproducing irregular forms, a pattern, a block, means to rotate the pattern and the block in unison, means carrying a rotating cutter adapted to operate on said block, means controlling the relative position of the cutter and block determined by the pattern, and a motor carried by the machine to rotate the cutter, means for feeding both the cutter and the motor past the block during the cutting action, and means supporting said cutter independently of the motor.

2. In a turning lathe of the kind described, means to support and rotate a last pattern, means to support and rotate a block on which the last is to be reproduced from said pattern, a cutter adapted to operate on said block, and means controlling the relative position of the cutter and the block determined by said pattern, guideways on which the cutter is supported, a motor to actuate said cutter, separate guideways on which said motor is supported, means to rotate the cutter from the motor, and means to feed both motor and cutter in unison from a single source of power during the last cutting operation.

HAROLD W. SPRAGUE.

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